Summary
The α-adrenoceptor blocking potency of WB 4101 at α1- and α2-adrenoceptors has been investigated in pithed rats.
WB 4101 was approximately 97 times more potent at antagonizing the vasopressor responses produced by the selective α1-adrenoceptor agonist phenylephrine, than those produced by the selective α2-adrenoceptor agonist M-7.
A dose of WB 4101 (3 mg/kg) that caused extensive blockade of vascular α1-adrenoceptors, but little or no blockade of vascular α2-adrenoceptors, exerted no significant blockade of the presynaptic α2-adrenoceptors in the rat heart.
The results support the view that WB 4101 is a highly selective antagonist at α1-adrenoceptors in vivo.
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Drew, G.M. Evidence in favour of a selective α1-adrenoceptor blocking action of WB 4101 in vivo. Naunyn-Schmiedeberg's Arch. Pharmacol. 319, 222–225 (1982). https://doi.org/10.1007/BF00495869
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DOI: https://doi.org/10.1007/BF00495869